SIST EN ISO 15512:2009
(Main)Plastics - Determination of water content (ISO 15512:2008)
Plastics - Determination of water content (ISO 15512:2008)
This International Standard specifies methods for the determination of the water content of plastics in the form of granules and finished articles. These methods do not test for water absorption (kinetics and equilibrium) of plastics as measured by ISO 62. The methods are suitable for the determination of water content as low as the following levels: - Method A 0,1 % or better; - Method B 0,01 % or better; - Method C 0,01 % or better. Water content is an important parameter for processing materials, and should remain below the level specified in the appropriate material standard. Three alternative methods are specified in this International Standard: a) Method A is an extraction method using anhydrous methanol followed by a Karl Fischer titration of the extracted water. It can be used for all plastics and is applicable to granules having a maximum size of 4 mm × 4 mm × 3 mm. b) Method B is a vaporization method using heated, dry air or nitrogen gas to evaporate the water, followed by a Karl Fischer titration of the collected water. It can be used for all plastics and is applicable to granules smaller than 4 mm × 4 mm × 3 mm. c) Method C is a manometric method. The water content is determined from the increase in pressure which results when the water is evaporated under a vacuum. This method is not applicable to plastic samples containing volatile compounds, other than water, in amounts contributing significantly to the vapour pressure at room temperature. Checks for the presence of large amounts of volatile compounds should be carried out periodically, for example by gas chromatography. Such checks are particularly required for new types or grades of material.
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2008)
1.1 Diese Internationale Norm legt Verfahren zur Bestimmung des Wassergehaltes von Kunststoffen fest, die als Granulat oder Fertigartikel vorliegen. Bei diesen Verfahren wird nicht die Wasseraufnahme (Kinetik und Gleichgewicht) von Kunststoffen geprüft, wie diese in ISO 62 gemessen wird. Diese Verfahren sind zur Bestimmung von Wassergehalten bis hinunter zu folgenden Werten vorgesehen:
Verfahren A 0,1 % oder besser;
Verfahren B 0,01 % oder besser;
Verfahren C 0,01 % oder besser.
Der Wassergehalt ist ein wichtiger Parameter bei der Verarbeitung von Werkstoffen und sollte stets unter dem in den entsprechenden Werkstoffnormen festgelegten Wert bleiben.
1.2 In dieser Internationalen Norm sind drei alternative Verfahren festgelegt:
a) Verfahren A ist ein Extraktionsverfahren mit wasserfreiem Methanol und anschließender Titration des Wassers nach dem Karl Fischer Verfahren. Es kann für alle Kunststoffe verwendet werden und ist auf Granulat mit der maximalen Korngröße von 4 mm 4 mm 3 mm anwendbar.
b) Verfahren B ist ein Verdampfungsverfahren, bei dem mit aufgeheizter trockener Luft oder Stickstoffgas Wasser verdampft wird, und anschließend die Titration des gesammelten Wassers nach dem Karl Fischer Verfahren erfolgt. Es kann für sämtliche Kunststoffe angewendet werden und ist auf Granulat kleiner als 4 mm 4 mm 3 mm anwendbar.
c) Verfahren C ist ein manometrisches Verfahren. Der Wassergehalt wird aus dem Druckanstieg nach dem Verdampfen des Wassers unter Vakuum bestimmt. Das Verfahren kann nicht auf Kunststoffproben angewendet werden, die andere flüchtige Bestandteile als Wasser in solchen Mengen enthalten, dass diese signifikant zum Dampfdruck bei Raumtemperatur beisteuern. In regelmäßigen Abständen sollte, z. B. durch Gaschromatographie, die Anwesenheit großer Mengen an flüchtigen Bestandteilen überprüft werden. Diese Überprüfungen sind insbesondere notwendig bei neuen Typen oder Klassen von Werk¬stoffen.
Plastiques - Dosage de l'eau (ISO 15512:2008)
L'ISO 15512:2008 spécifie des méthodes pour le dosage de l'eau dans les plastiques sous forme de granulés et d'articles finis. Ces méthodes ne contrôlent pas l'absorption d'eau (cinétique et équilibre) des plastiques, cet aspect étant traité dans l'ISO 62. Les méthodes sont applicables au dosage de l'eau à des niveaux aussi faibles que les suivants:
Méthode A 0,1 % ou mieux;
Méthode B 0,01 % ou mieux;
Méthode C 0,01 % ou mieux.
La teneur en eau est un paramètre important de la mise en œuvre des matériaux et il convient qu'elle reste en dessous du niveau spécifié dans la norme de produit appropriée.
Trois méthodes possibles sont spécifiées:
La méthode A consiste en une extraction de l'eau à l'aide de méthanol anhydre suivie d'un titrage de l'eau extraite par la méthode de Karl Fischer. Elle est applicable aux granulés de dimensions maximales 4 mm x 4 mm x 3 mm et peut être utilisée pour tous les plastiques.
La méthode B procède par vaporisation de l'eau à l'aide d'air sec ou d'azote gazeux chauffé suivie d'un titrage de l'eau recueillie par la méthode de Karl Fischer. Elle est applicable aux granulés de moins de 4 mm x 4 mm x 3 mm et peut être utilisée pour tous les plastiques.
La méthode C est une méthode manométrique. Le dosage se fonde sur l'augmentation de pression après évaporation de l'eau sous vide. Cette méthode n'est pas applicable aux échantillons de plastiques contenant des composés volatils, autres que l'eau, en quantité suffisante pour avoir un effet significatif sur la pression de vapeur à température ambiante. Il convient d'effectuer périodiquement des vérifications de la présence de grandes quantités de composés volatils, par exemple par chromatographie en phase gazeuse. Ces vérifications sont particulièrement nécessaires pour les nouveaux types ou les nouvelles qualités de matériaux.
Polimerni materiali - Določevanje vode (ISO 15512:2008)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 15512:2009
01-december-2009
1DGRPHãþD
SIST EN ISO 15512:2004
3ROLPHUQLPDWHULDOL'RORþHYDQMHYRGH ,62
Plastics - Determination of water content (ISO 15512:2008)
Kunststoffe - Bestimmung des Wassergehaltes (ISO 15512:2008)
Plastiques - Dosage de l'eau (ISO 15512:2008)
Ta slovenski standard je istoveten z: EN ISO 15512:2009
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 15512:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 15512:2009
---------------------- Page: 2 ----------------------
SIST EN ISO 15512:2009
EUROPEAN STANDARD
EN ISO 15512
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2009
ICS 83.080.01 Supersedes EN ISO 15512:2003
English Version
Plastics - Determination of water content (ISO 15512:2008)
Plastiques - Dosage de l'eau (ISO 15512:2008) Kunststoffe - Bestimmung des Wassergehaltes (ISO
15512:2008)
This European Standard was approved by CEN on 20 June 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15512:2009: E
worldwide for CEN national Members.
---------------------- Page: 3 ----------------------
SIST EN ISO 15512:2009
EN ISO 15512:2009 (E)
Contents Page
Foreword .3
2
---------------------- Page: 4 ----------------------
SIST EN ISO 15512:2009
EN ISO 15512:2009 (E)
Foreword
The text of ISO 15512:2008 has been prepared by Technical Committee ISO/TC 61 “Plastics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 15512:2009 by
Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by NBN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by January 2010, and conflicting national standards shall be withdrawn at
the latest by January 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 15512:2003.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 15512:2008 has been approved by CEN as EN ISO 15512:2009 without any modification.
3
---------------------- Page: 5 ----------------------
SIST EN ISO 15512:2009
---------------------- Page: 6 ----------------------
SIST EN ISO 15512:2009
INTERNATIONAL ISO
STANDARD 15512
Second edition
2008-05-15
Plastics — Determination of water
content
Plastiques — Dosage de l'eau
Reference number
ISO 15512:2008(E)
©
ISO 2008
---------------------- Page: 7 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2008
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Method A — Extraction with anhydrous methanol . 2
3.1 Principle. 2
3.2 Reagents. 2
3.3 Apparatus . 2
3.4 Preparation of test sample. 2
3.5 Procedure . 3
3.6 Expression of results . 3
3.7 Precision. 4
4 Method B — Water vaporization. 4
4.1 Principle. 4
4.2 Reagents. 4
4.3 Apparatus . 5
4.4 Preparation of sample . 6
4.5 Procedure . 6
4.6 Expression of results . 8
4.7 Precision. 8
5 Method C — Manometric method. 8
5.1 Principle. 8
5.2 Reagent. 8
5.3 Apparatus . 9
5.4 Preparation of sample . 9
5.5 Procedure . 11
5.6 Expression of results . 13
5.7 Precision. 13
6 Test report . 13
Annex A (informative) Selection of the optimum heating temperature for the water content
determination . 14
Bibliography . 16
© ISO 2008 – All rights reserved iii
---------------------- Page: 9 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15512 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-
chemical properties.
This second edition cancels and replaces the first edition (ISO 15512:1999), which has been technically
revised.
iv © ISO 2008 – All rights reserved
---------------------- Page: 10 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
Introduction
The inter-laboratory comparability of water content determinations is often low. Major causes for this are the
sample packaging, sample handling and differences between equipment and settings. In order to be able to
compare data between two laboratories, special care needs to be taken with sample packaging and sample
handling. Samples should e.g. be packed in special glass containers or water barrier sealed bags. Sample
handling should preferably be carried out in a dry nitrogen or air environment. To improve the repeatability and
reproducibility, the procedure specified in this International Standard should be followed strictly.
The temperature settings for the vaporization method described in this International Standard are not specified
in the standard. For the manometric method, a temperature of 200 °C is often used. However, for some
condensation materials this might be too high and could e.g. cause generation of water due to a condensation
reaction.
The heating temperature should be optimized concerning the material to be tested, the equipment in use and
the practical circumstances. If the temperature is too low, the total amount of water in the material to be tested
will not be evaporated completely, whereas too high temperatures cause water generation due to effects like
degradation and condensation reactions.
In this International Standard, a procedure is included for optimization of the heating temperature in order to
choose the correct temperature for the water content determination and to improve the inter-laboratory
comparability.
© ISO 2008 – All rights reserved v
---------------------- Page: 11 ----------------------
SIST EN ISO 15512:2009
---------------------- Page: 12 ----------------------
SIST EN ISO 15512:2009
INTERNATIONAL STANDARD ISO 15512:2008(E)
Plastics — Determination of water content
1 Scope
1.1 This International Standard specifies methods for the determination of the water content of plastics in
the form of granules and finished articles. These methods do not test for water absorption (kinetics and
equilibrium) of plastics as measured by ISO 62. The methods are suitable for the determination of water
content as low as the following levels:
⎯ Method A 0,1 % or better;
⎯ Method B 0,01 % or better;
⎯ Method C 0,01 % or better.
Water content is an important parameter for processing materials, and should remain below the level specified
in the appropriate material standard.
1.2 Three alternative methods are specified in this International Standard:
a) Method A is an extraction method using anhydrous methanol followed by a Karl Fischer titration of the
extracted water. It can be used for all plastics and is applicable to granules having a maximum size of
4 mm × 4 mm × 3 mm.
b) Method B is a vaporization method using heated, dry air or nitrogen gas to evaporate the water, followed
by a Karl Fischer titration of the collected water. It can be used for all plastics and is applicable to
granules smaller than 4 mm × 4 mm × 3 mm.
c) Method C is a manometric method. The water content is determined from the increase in pressure which
results when the water is evaporated under a vacuum. This method is not applicable to plastic samples
containing volatile compounds, other than water, in amounts contributing significantly to the vapour
pressure at room temperature. Checks for the presence of large amounts of volatile compounds should
be carried out periodically, for example by gas chromatography. Such checks are particularly required for
new types or grades of material.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 760, Determination of water — Karl Fischer method (General method)
© ISO 2008 – All rights reserved 1
---------------------- Page: 13 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
3 Method A — Extraction with anhydrous methanol
3.1 Principle
A test portion is extracted with anhydrous methanol and the extracted water determined by titration using the
Karl Fischer method.
3.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
3.2.1 Methanol, anhydrous, having a water content less than 0,1 % by mass.
3.2.2 Karl Fischer reagent, with an equivalence factor of approximately 3 mg/ml to 5 mg/ml of water. If the
reagent is prepared, check its equivalence factor as specified in ISO 760.
3.3 Apparatus
Ordinary laboratory apparatus and the following:
3.3.1 Glass flasks, 250 ml capacity, provided with ground-glass or rubber stoppers.
3.3.2 Conical titration flasks, 150 ml capacity, with standard ground necks and provided with
ground-glass stoppers.
3.3.3 Reflux condensers, with ground neck capable of being fitted on to the flasks (3.3.2) and on to the
tubes (3.3.4).
3.3.4 Water-absorption tubes with ground joints, containing calcium chloride or other drying agent.
3.3.5 Electrical or hot-air heaters, for the flasks (3.3.2).
3.3.6 Pipettes, 50 ml capacity. (Automatic filling pipettes are acceptable.)
3.3.7 Woulfe bottles, with two tubes.
3.3.8 Curved or U-shaped water-absorption tubes, filled with calcium chloride.
3.3.9 Rubber pipette filler.
3.3.10 Pipette, 10 ml capacity.
3.3.11 Desiccator, containing calcium chloride.
3.3.12 Analytical balance, accurate to 0,2 mg.
3.3.13 Karl Fischer apparatus, for determining water content in accordance with ISO 760.
3.4 Preparation of test sample
3.4.1 Granules
Take a representative sample of approximately 100 g. Put the sample into a pre-dried glass flask (3.3.1) and
immediately close it with a stopper.
NOTE It is desirable to pre-dry the container in an oven, then cool it over a suitable water absorbent, for instance
silica gel.
2 © ISO 2008 – All rights reserved
---------------------- Page: 14 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
3.4.2 Finished articles
Cut or saw the sample into pieces of appropriate size, i.e. having a maximum size of 4 mm × 4 mm × 3 mm.
Proceed quickly to minimize moisture absorption.
3.5 Procedure
3.5.1 Precautions
Due to the low quantities of water measured, maximum care shall be exercised at all times to avoid
contaminating the sample with water from the sample container, the atmosphere or transfer equipment.
Hygroscopic resin samples shall be protected from the atmosphere.
3.5.2 Preparation of test portions
Conduct the test on two test portions from the same sample. Use test portions containing 10 mg to 20 mg of
water based on the estimated water content of the sample.
3.5.3 Determination
Carefully dry the apparatus.
Weigh each test portion to the nearest 1 mg into a conical titration flask (3.3.2) fitted with a ground-glass
stopper. Pipette 50 ml (3.3.6) of anhydrous methanol (3.2.1) into the conical flask containing the test portion.
At the same time, add 50 ml of anhydrous methanol to another conical flask for a blank test. Stopper the
flasks. Keep the stoppered flasks in the desiccator (3.3.11) pending continuation of the test.
Unstopper the flasks and quickly attach them to reflux condensers (3.3.3) fitted with calcium chloride tubes
(3.3.4). Reflux the contents of the conical flasks for 3 h, then leave them for 45 min to cool to room
temperature. Separate the flasks from the condensers, quickly stopper them and place them in the desiccator.
Use the Karl Fischer apparatus (3.3.13) to titrate the contents of each flask with Karl Fischer reagent (3.2.2).
3.6 Expression of results
The water content w, expressed as a percentage by mass, for each of the two determinations is given by the
following formula:
VV− T
()
12
w=×100
m
where
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the determination;
1
V is the volume, expressed in millilitres, of Karl Fischer reagent used for the blank test;
2
T is the water equivalent, expressed in grams of water per millilitre of reagent, of Karl Fischer reagent;
m is the mass, in grams, of the test portion.
The two values for the water content shall not differ by more than 10 % relative or 0,02 % absolute, whichever
is the greater. If the difference is greater, repeat the measurements until acceptable consecutive values are
obtained and discard all unacceptable results.
The result is expressed as the average of these two determinations, rounded to the nearest 0,01 % by mass.
© ISO 2008 – All rights reserved 3
---------------------- Page: 15 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
3.7 Precision
The precision of this test method is not known because interlaboratory data are not available. If and when
interlaboratory data are obtained, a precision statement will be added at a subsequent revision.
4 Method B — Water vaporization
4.1 Principle
A test portion is weighed then placed in an oven. The water contained in the test portion is vaporized and
carried to the titration cell by a dry nitrogen carrier gas. The water is then titrated using the coulometric Karl
Fischer method. This method is based on the reduction of iodine by sulfur dioxide in the presence of water to
form sulfur trioxide and hydroiodic acid as follows:
I + SO + H O → 2HI + SO
2 2 2 3
Unlike the conventional Karl Fisher reagents that include iodine, the coulometric technique generates the
iodine electrolytically from iodide
− −
2I → I + 2e
2
with 10,71 C of generating current corresponding to 1 mg of water in accordance with Faraday’s law.
4.2 Reagents
During the analysis, use only reagents of recognized analytical grade and only distilled water or water of
equivalent purity.
4.2.1 Anode solution, containing iodide ions to generate iodine in the reaction mixture, in accordance with
the equipment manufacturer's instructions (for use when a titration cell with a diaphragm is being used).
4.2.2 Cathode solution, containing a suitable salt in methanol (or another suitable organic solvent),
prepared in accordance with the equipment manufacturer’s instructions (for use when a titration cell with a
diaphragm is being used).
4.2.3 Universal reagent, containing iodide ions to generate iodine in the reaction mixture, prepared in
accordance with the equipment manufacturer’s instructions (for use when a titration cell without a diaphragm
is being used).
4.2.4 Neutralization solution, consisting of approximately 4 mg/ml of water in propylene carbonate,
ethylene glycol monomethyl ether (2-methoxyethanol) or methyl cellosolve.
4.2.5 Silica gel, in the form of granules of approximately 2 mm diameter, for use as a desiccant.
®1)
4.2.6 SICAPENT molecular sieve or phosphorus pentoxide, for use as a carrier-gas desiccant.
4.2.7 Grease, containing little or no water and having low water absorptivity, for lubricating the ground-glass
joints to maintain the airtightness of the system.
4.2.8 Nitrogen gas (N ), containing less than 5 µg/g of water.
2
®
1) SICAPENT is a trade name of MERCK. It is an example of a suitable product available commercially. This
information is given for the convenience of users of this International Standard and does not constitute an endorsement by
ISO of this product.
4 © ISO 2008 – All rights reserved
---------------------- Page: 16 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
4.3 Apparatus
Ordinary laboratory apparatus and the following:
4.3.1 Coulometric Karl Fischer titrator, consisting of a control unit and a titration-cell assembly equipped
with a generator cell with or without a diaphragm, dual platinum sensing electrodes and a magnetic stirrer (see
Figure 1). The instrument is designed to coulometrically generate iodine that reacts stoichiometrically with the
water present in the cell. The number of coulombs of electricity required to generate the reagent are converted
to micrograms of water which is given as a direct digital readout.
A diaphragm-free cell is accurate enough for many applications. However, check with the equipment supplier
to verify whether the particular applications for which this method is being used require a diaphragm. A cell
with a diaphragm is recommended if the best possible accuracy is required.
4.3.2 Water vaporizer, consisting of an oven capable of heating the test portion to at least 300 °C, a
heating tube, a temperature control unit, a carrier-gas flowmeter and carrier-gas drying tubes containing
desiccant (see Figures 1 and 2).
Key
1 coulometric Karl Fischer meter 7 oven
2 exhaust gas 8 heating tube
3 titration cell 9 water-absorption tubes (filled with desiccant, for example P O )
2 5
4 titration controller 10 flowmeter
5 power supply 11 temperature controller
6 water vaporizer 12 N gas
2
Figure 1 — Flow chart of system used for the determination of water content using method B
© ISO 2008 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
a) Push-bar type
b) Magnet type
Key
1 sample boat 3 sample-boat inlet
2 sample inlet 4 magnet
Figure 2 — Heating tubes
4.3.3 Microsyringe, capacity 10 µl, calibrated.
4.3.4 Sample boat: Aluminium foil may be used to hand fashion a disposable boat large enough to contain
the sample and small enough to fit into the heating tube.
4.4 Preparation of sample
The test material may be in any form, such as granules, moulding powder, fabricated shapes or moulded
items.
Cut fabricated shapes and moulded items to a suitable size. Granules shall be smaller than
4 mm × 4 mm × 3 mm.
Take a representative sample of u 10 g. Due to the small size of the sample, care shall be taken to ensure
that it is in fact representative.
4.5 Procedure
4.5.1 Precautions
Due to the low quantities of water measured, maximum care shall be exercised at all times to avoid
contaminating the sample with water from the sample container, the atmosphere or transfer equipment.
Hygroscopic resin samples shall be protected from the atmosphere.
6 © ISO 2008 – All rights reserved
---------------------- Page: 18 ----------------------
SIST EN ISO 15512:2009
ISO 15512:2008(E)
4.5.2 Preparation of apparatus
Refer to Figure 1 for the following procedure.
Assemble the water vaporizer (4.3.2) and coulometric Karl Fischer titrator (4.3.1) as directed in the
manufacturer’s instructions. Fill the absorption tubes with desiccating agent (see 4.3.2) as directed in the
manufacturer’s instructions.
Pour approximately 200 ml (adjust for the container size) of the anode solution (4.2.1) into the generator cell
and 10 ml of the cathode solution (4.2.2) into the cathode solution cell [or use the universal reagent (4.2.3) if a
titration cell without a diaphragm is being used]. The surface of the cathode solution shall be below the level of
the anode solution to prevent backflow contamination of the cathode solution.
Turn the cell power switch on. If the cell potential shows a negative value, indicating that the anode solution
contains an excess of iodine, add 50 µl to 200 µl of the neutralization solution (4.2.4).
Disconnect the tube connecting the vaporizer unit to the titration cell. Set the carrier-gas flow to 200 ml/min to
300 ml/min and heat the oven to the desired temperature to remove any residual water from the vaporizer
(4.3.2).
Lift the titration cell and agitate the solution by gently swirling the cell to remove any residual water from the
walls. Stir the solution for a minute in the TITRATION mode to dry and stabilize the inner atmosphere.
Re-connect the tube from the vaporizer unit to the titration cell. Keep the carrier-gas flow on during the whole
titration. The instrument is now ready for sample analysis.
4.5.3 Equipment check
4.5.3.1 To check if the coulometric Karl Fisher titrator is functioning properly, carry out a determination
with a known amount of water as follows: With the analyser stabilized and in the READY position, press the
start switch and carefully inject 5 µl of water into the cell using a 10 µl syringe (4.3.3). When the END light
comes on, record the reading. This reading should be (5 000 ± 250) µg.
4.5.3.2 To check if the whole system is functioning properly, carry out a determination with 50 mg of
sodium tartrate dihydrate (Na C H O⋅2H O) at 150 °C. Follow 4.5.3.1 to measure the quantity of water
2 4 4 6 2
contained in the sodium tartrate dihydrate. The result should be (15,6 ± 0,5) %.
4.5.4 Determination
Heat the oven to the desired temperature and place the sample boat (4.3.4) in the heating tube and push it
into the oven to dry and also to backpurge any residual water contained in the sample-boat inlet.
For the heating temperature, the user is referred to
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.